Powered sled

ABSTRACT

A pallet sled includes a base and a pair of tines extending from the base. A load wheel supports outer ends of each of the tines. A wheel supports the base. At least one motor is configured to drive the base wheel or at least one of the load wheels for driving the pallet sled. The motor may be a hub motor inside the base wheel or the load wheel.

BACKGROUND

There are many environments within the food service and retailindustries, such as restaurants, office complexes, retail stores andhospitals, that do not allow electric lifts inside due to the actual orperceived threat of being too heavy, bulky, or risky in terms ofpotentially causing store damage.

SUMMARY

The powered sled disclosed herein increases delivery efficiencies byreducing the amount of time and labor an operator needs to deliverproduct (raw goods, finished goods, etc.) to the food service or retailenvironment. The sled may allow the driver to transport a fully loadedpallet directly from the trailer to inside the store without having todown stack product onto a hand truck and make multiple trips back andforth.

This powered sled includes an electric motor or motors and batteries toprovide propulsion in forward and reverse. The powered drive isespecially useful when moving heavy pallet loads across parking lots, upramps and slopes, and over thresholds that may be encountered throughoutthe delivery process. The batteries may also provide power to lift thepallet load, or a hydraulic foot pump may be utilized, similar to anexisting delivery sled.

This lightweight powered sled would be allowed in those environments,would provide powered drive to the operator and still maintain all thebenefits of existing sled designs, such as lightweight, compact design,highly maneuverable and zero turn radius about the load wheels.

The sleekness of the compact and concealed electric drive componentswould ensure that the powered sled is never mistaken for a heavyelectric lift and would operate with very minimal noise, which is idealfor the food service and retail environments, especially when customersare also in the vicinity.

The electric motors may be powered by an external battery pack that ismounted to the rear of the sled near the operator and can be quickly andeasily removed and replaced with a fully charged battery when depleted.Also, the battery pack may be easily accessed and does not need to beremoved from the sled in order to plug in and charge the batteries whenthe sled is not in use, such as in between delivery stops on thetrailer, or in the warehouse at the end of the delivery day.

The preset motor parameters, such as maximum speed, acceleration rates,decelerations rates, braking rates, throttle maps, etc, may becontrolled by an electronic motor controller that is mounted within theframe of the sled and connected to the motor(s) and battery pack. Theseparameters are set by the manufacturer, but the customer may also beable to adjust certain parameters, depending on user preference,intended usage and/or environment.

The powered drive and speed of the sled may be controlled by theoperator via a throttle control mounted to the handlebars and iscompletely optional. The powered sled operates just like a traditionalmanual sled (operator pushes the sled and associated load) when notusing the motor(s) and the drive mechanism allows the wheels to“freewheel” or spin freely without added friction when disengaged frompower. This is helpful in tight environments, such as coolers orfreezers, or when powered drive is not allowed, such as in certain storeenvironments.

The sled may also have a brake lever or switch that applies a brakingforce via regenerative braking through the hub motors. This is helpfulfor the operator to reduce speed and assist in maintaining control ofthe sled, especially when going down slopes and ramps.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a pallet sled according to oneembodiment.

FIG. 2 shows the sled of FIG. 1 with the rear panel removed.

FIG. 3 is a bottom view of the sled of FIG. 1.

FIG. 4 is a side view of the sled of FIG. 1.

FIG. 5 is a rear view of the sled 10.

FIG. 6 is a front view of the sled 10.

FIG. 7 is a top view of the sled 10.

FIG. 8 is an enlarged view of the bottom of a forward end of one of thetines of the sled of FIG. 1.

FIG. 9 is a perspective view of the forward end of the tine of FIG. 8.

FIG. 10 is an exploded perspective view of the forward end of the tineof FIG. 8.

FIG. 11 is a perspective view of a sled according to a secondembodiment.

FIG. 12 is an enlarged view of the bottom of a forward end of one of thetines of the sled of FIG. 11.

FIG. 13 is a perspective view of a sled according to a third embodiment.

FIG. 14 is an enlarged view of the bottom of a forward end of one of thetines of the sled of FIG. 13.

FIG. 15 is a perspective view of a sled according to a fourthembodiment.

FIG. 16 is an enlarged view of a lower portion of the base of the sledof FIG. 15.

FIG. 17 is a perspective view of a sled according to a fifth embodiment.

FIG. 18 is an enlarged view of a lower portion of the base of the sledof FIG. 17.

FIG. 19 is a perspective view of a control system that could be used inany of the above sled embodiments.

FIG. 20 is an enlarged view of the throttle control of FIG. 19.

FIG. 21 is an enlarged view of the lift control of FIG. 19.

DETAILED DESCRIPTION

A powered sled 10 for transporting pallets is shown in FIG. 1. The sled10 includes a lift module or base 12 connected to a pair of tines 14.The base 12 can raise and lower the tines 14, such as by leveraging theload wheels 16 supporting outer ends of the tines 14. Casters 18 maysupport the base 12.

A battery 22 is also mounted in the base 12 for driving motors withinthe load wheels 16, as will be explained below. Upright handles 24extend upward from the base 12. A lift control 26 is connected to thehandles 24. A throttle control 28 is also connected to the handles 24.

FIG. 2 shows the sled 10 with a rear cover removed. The sled 10 that isshown includes an electro-hydraulic pump 20 for raising and lowering thetines 14. The pump 20 may be powered by the removable battery 22.Alternatively, a hydraulic foot pump or other mechanism for lifting thetines 14 may be utilized.

FIG. 3 is a bottom view of the sled 10. Referring to FIG. 3, each loadwheel 16 is mounted at the end of a pair of arms 34, which are pivotablymounted at opposite ends to the tine 14 at pivot axis 32. As iswell-known, a push rod 30 leverages the arms 34 up and down to raise andlower the load wheels 16. In this example, the push rods 30 are poweredby the pump 20 (FIG. 2) as controlled by the lift control 26 (FIG. 1).

In this embodiment, the load wheels 16 include hub motors 17. The hubmotors 17 selectively receive power from the battery 22 (FIG. 1) todrive the load wheels 16 rotatably. Both hub motors 17 may be controlledby the single throttle 28 (FIG. 1). Alternatively, dual throttlecontrols (one for each hub motor 17) would allow the operator to steerthe sled 10. A free spinning lead wheel 36 is mounted at the front ofeach tine 14 and spaced above the floor (FIG. 4) to assist in contactwith curbs, ramps, etc. As another alternative, a hub motor 17 may beprovided in only one of the load wheels 16, while the other load wheelis free spinning.

FIG. 5 is a rear view of the sled 10. FIG. 6 is a front view of the sled10. FIG. 7 is a top view of the sled 10.

FIGS. 8 and 9 are enlarged bottom views of the forward end of one of thetines 14. Again, the load wheel 16 is mounted between a pair of arms 34via the hub motor 17, which can receive power (e.g. electrical power)via a conduit 38 from the battery 22 (FIG. 2) as controlled by thethrottle control 28 (FIG. 2). As is known, the forward portion of thearms 34 engages the load wheel 16, while the push rod 30 engages a rearportion of the arms 34 rearward of the axis 32. The rear portion of thearms 34 angles upward. As is known, axial movement of the pushrod 30toward the outer end of the tine 14 causes the arms 34 to pivot aboutthe axis 32 and causes the load wheel 16 to pivot downward relative tothe tine 14, thereby lifting the tine 14 relative to the floor. Axialmovement of the pushrod 30 away from the outer end of the tine 14 causesthe arms 34 to pivot about the axis 32 and causes the load wheel 16 topivot upward toward to the tine 14, thereby lowering the tine 14relative to the floor.

Referring particularly to FIG. 10, the forward ends of the arms 34 eachinclude a slot 40 for receiving an axle 42 of the hub motor 17, aboutwhich the load wheel 16 is rotated by the hub motor 17. The slots 40 areelongated and substantially vertical angling slightly forward andopening downwardly. The axle 42 may have flats to prevent rotation ofthe axle 42 within the slot 40. The axle 42 is secured in the slots 40by a pair of keyed washers 41 and a pair of axle nuts 43. The keyedwashers 41 include projections received in apertures in the arm 34. Thekeyed washers 41 also include apertures complementary to the flats onthe axle 42. By loosening the axle nuts and removing the keyed washers41, the load wheel 16 can be slid out of the slot 40. A quick connect orother electrical coupling can easily disconnect the hub motor 17 fromwiring 44 in the conduit 38. The rest of the wiring 44 is routed withinthe fork tine 14 where it is protected. In this manner it is relativelyeasy to remove and replace the wheel 16 and hub motor 17 if necessary.

FIGS. 11 and 12 show a sled 110 according to a second embodiment, whichis similar to that of FIGS. 1-10, except as otherwise described orshown. Referring to FIG. 11, the sled includes a base 112 connected to apair of tines 114. Each tine 114 includes a primary load wheel 115adjacent an outer end thereof. In this embodiment, a hub motor 117 in asecondary load wheel 116 is operated in tandem with the primary loadwheel 115 in each tine 114.

Referring to FIG. 12, the primary load wheel 115 and hub motor 117 areeach mounted to ends of a pair of tandem plates 140. The tandem plates140 are pivotably mounted near their centers to outer ends of the arms134, which raise and lower the primary load wheel 115 and hub motor 117(with secondary load wheel 116) relative to the tine 114 (to raise andlower the tine 114). Both the primary load wheel 115 and secondary loadwheel 116 contact the floor. This provides load distribution between thesecondary load wheel 116 and the primary load wheel 115 and mayfacilitate easier climbs over thresholds, for example.

As with the first embodiment, the hub motor 117 in tandem with thesecondary load wheel 116 may be placed under both tines 114 or,alternatively, only under one of the two tines 114. Also, optionally,the hub motor 117 may be mounted in front of or behind the primary loadwheel 115. A conduit 138 provides power to each hub motor 117.

FIGS. 13 and 14 show a powered sled 210 according to a third embodiment,which is similar to that of FIGS. 1-10, except as otherwise described orshown. The sled 210 includes a base 212 connected to a pair of tines214, as before. The tines 214 are supported by load wheels 216 towardouter ends thereof, which are raised and lowered as before.

FIG. 14 is a bottom perspective view of one of the tines 214. The loadwheel 216 is rotatably mounted at outer ends of the arms 234, which arepivotable to raise and lower the load wheel 216 relative to the tine 214as driven by push rod 230. A drive motor 217 is mounted adjacent theload wheel 216 and secured to the tine 214. The motor 217 drives theload wheel 216 via a pair of pulleys 244, 248 and a belt 246.Alternatively gears or other mechanisms could be used to connect themotor 217 to the drive wheel 216. Again the drive motor 217 could beinstalled under both or just a single one of the tines 214.

FIGS. 15 and 16 show a powered sled 310 according to a fourthembodiment, which is similar to that of FIGS. 1-10, except as otherwisedescribed or shown. The sled 310 includes a base 312 connected to thetines 314. A load wheel 316 supports outer ends of each of the tines314. In this embodiment, the wheels 318 under the base 312 include hubmotors 317, again controlled by the throttle 328. Locating the hubmotors under the base 312 instead of under the tines 314 permits largerwheels and larger hub motors to be used. Again, hub motors 317 could beplaced in both wheels 318 or just one of the wheels 318. Optionally, oneor more hub motors could also be placed in the load wheels under thetines as well. The hub motors 317 would be powered by the battery 322 ascontrolled by the throttle control 328.

FIGS. 17 and 18 show a powered sled 410 according to a fifth embodimentwhich is similar to that of FIGS. 1-10, except as otherwise described orshown. The sled 410 includes a base 412 connected to the tines 414. Aload wheel 416 supports outer ends of each of the tines 414. In thisembodiment, there are two free-spinning wheels 418 and a single hubmotor 417 and drive wheel 420 mounted between the free-spinning wheels418. The hub motor 417 is again controlled by the throttle 428. The hubmotor 417 of the drive wheel 420 would be powered by the battery 422 asselectively controlled by the throttle controller 428.

FIGS. 19-21 show a control system 510 that could be used with the sledsof any of the above embodiments. A pair of grips 540 are mounted togenerally vertical handlebars 541. A lift control 526 projects inwardfrom one grip 540, while a throttle control 528 projects inward from theother grip 540. Referring to FIG. 20, the throttle control 528 includesa lever 542 biased to a middle position. The user can move the lever 542upward with a thumb to drive the sled forward, or downward to drive thesled rearward. The speed may be controlled by how far the user moves thelever 542. Releasing the lever 542 returns the lever 542 to the center,stop position. The lever 542 also operates as a brake, by moving thelever 542 in the direction opposite movement of the sled. A throttleinterlock may be integrated onto the front of the controls to beactuated by the user's fingers. This throttle interlock must first bepressed in before the lever 542 can be moved upward or downward toprevent unintended actuation of the drive system. Optionally thethrottle interlock could be installed on the opposite grip 540 torequire two-handed operation of the sled.

Referring to FIG. 21, the lift control 526 includes a rocker switch 544.Pressing the rocker switch 544 upward causes the tines to be raised.Pressing the rocker switch 544 downward causes the tines to be lowered.Releasing the rocker switch 544 returns the switch 544 to a middle, stopposition.

In accordance with the provisions of the patent statutes andjurisprudence, exemplary configurations described above are consideredto represent a preferred embodiment of the invention. However, it shouldbe noted that the invention can be practiced otherwise than asspecifically illustrated and described without departing from its spiritor scope.

What is claimed is:
 1. A pallet sled comprising: a base; a first tineand a second tine extending from the base; a first arm pivotably mountedto the first tine; a second arm pivotably mounted to the second tine; afirst load wheel mounted to the first arm and supporting an outer end ofthe first tine; a second load wheel mounted to the second arm andsupporting an outer end of the second tine; a rod in each of the firsttine and the second tine configured to pivot the first arm and thesecond arm to move the first load wheel and the second load wheel towardand away from the first tine and the second tine, respectively; a firsthub motor within the first load wheel for driving the pallet sled,wherein the first hub motor is mounted to the first arm, wherein thefirst hub motor includes an axle received in a slot in the first arm;and a washer keyed to the first arm and an axle nut secured to the axleoutward of the washer.
 2. The pallet sled of claim 1 further including asecond hub motor within the second load wheel.
 3. The pallet sled ofclaim 1 wherein the axle includes flat surfaces complementary to andengaging inner surfaces defining the slot.
 4. The pallet sled of claim 1further including a removable battery pack received in the base, thebattery pack configured to selectively operate the first hub motor.